Founder of Bridgewater, world's largest hedge fund, returned 14% last year before fees—2% of assets, 20% of profits—amid market turmoil. Dabbles in myriad markets: currencies, stocks, bonds, interest rates. Son of a jazz musician bought first stock at age 12. Harvard M.B.A. 1973. Became futures trader at brokerage CBWL-Hayden Stone. Left to found Bridgewater Associates at age 25. Today firm manages $67 billion. Contrarian culture: employees encouraged to find fault with superiors' decisions. Bow-hunter meditates 5 times a week.